With more than 120,000 domains currently registered, mothballing .su now would be a messy operation.
"It's like blocking .com or .org," said Komarov. "Lots of legitimate domains are registered there."
Among them are stalin.su, which eulogizes the Soviet dictator and the English-language chronicle.su, an absurdist parody site.
But experts say many are fraudulent, and even the organization behind .su accepts it has a problem on its hands.
"We realize it's a threat for our image," said Sergei Ovcharenko, whose Moscow-based nonprofit Foundation for Internet Development took responsibility for .su in 2007.
Ovcharenko insisted that only a small number of .su sites are malicious, although he acknowledged that criminal sites can stay online for extremely long periods of time. He said his hands were tied by weak Russian legislation and outdated terms of service. But he promised that stricter rules are on their way after months of legal leg work.
"We are almost there," he said. "This summer, we'll be rolling out our new policy."
Meanwhile .su has become an increasingly notorious corner of the Internet, an online echo of the evil empire moniker assigned to the Soviet Union by U.S. President Ronald Reagan 30 years ago.
David, the RSA manager, said the emergence of a Communist relic as a 21st century security threat was a bizarre blast from the past.
"I thought that the Berlin Wall and my grandma's borscht are the only remnants of the Soviet Union," he said. "I was wrong."
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